This is an in vitro testing and date gathering exercise. The rabbit pyrogen test is the classical test for endotoxin. However, the in vitro Limulus Amebocyte Lysate (LAL) test is gradually replacing the rabbit. The LAL test besides being more specific for endotoxin than the rabbit it is also more quantitative. We are gathering data on biological products. It is our intention that over 90% of the products now being tested in rabbits will (in less than a year) be converted to the LAL test.